Open-Cell Spray Foam in Jackson, TN

Open-cell spray foam is the workhorse for sealing and covering large areas affordably. It expands to fill a cavity, forms an excellent air seal, and runs about R-3.8 per inch. For attics and interior walls where you want to stop air movement and quiet the house without paying for the densest product on the market, open-cell is often the smart choice.

How it differs from closed-cell

Open-cell foam has a softer, spongier structure — its cells aren’t fully closed, so it’s lighter and expands much more, filling irregular spaces and hard-to-reach gaps. That lower density is why its R-value per inch (about R-3.8, per Johns Manville) is lower than closed-cell’s R-7 — but in a big open attic with plenty of depth, that’s rarely the limiting factor. What matters most there is the air seal, and open-cell delivers it beautifully.

Where open-cell shines

• Attic rooflines and ceiling planes — excellent air sealing and coverage over large areas at a lower cost per square foot.
• Interior walls — its sound-deadening quality makes rooms noticeably quieter.
• Filling irregular cavities — the high expansion reaches gaps a denser foam or a batt would miss.

The honest limits — important in a humid climate

Open-cell is not a vapor barrier, and that matters more here than in a dry climate. Where moisture control is the goal — a crawl space, a rim joist, a metal building — that’s closed-cell territory. And because open-cell is lower R-value per inch, it needs more thickness to hit a given R-value, which is fine in an open attic but not in a shallow cavity. As always, we match the foam to the space rather than defaulting to one product.